AUTHOR=Gu Yifan , Han Wensu , Wang Yuquan , Liang Danlei , Gao Jinglin , Zhong Yihai , Zhao Shan , Wang Shijie 

TITLE=Xylocopa caerulea and Xylocopa auripennis harbor a homologous gut microbiome related to that of eusocial bees

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1124964

DOI=10.3389/fmicb.2023.1124964

ISSN=1664-302X

ABSTRACT=<sec><title>Background</title><p>Eusocial bees, such as bumblebees and honey bees, harbor host-specific gut microbiota through their social behaviors. Conversely, the gut microbiota of solitary bees is erratic owing to their lack of eusocial activities. Carpenter bees (genus <italic>Xylocopa</italic>) are long-lived bees that do not exhibit advanced eusociality like honey bees. However, they often compete for nests to reproduce. <italic>Xylocopa caerulea</italic> and <italic>Xylocopa</italic> auripennis are important pollinators of wild plants on Hainan Island. Whether they have host-specific bacteria in their guts similar to eusocial bees remains unknown.</p></sec><sec><title>Methods</title><p>We targeted the bacterial 16S rRNA V3-V4 region to investigate the diversity of bacterial symbionts in the fore-midgut and hindgut of two carpenter bees, <italic>X. caerulea</italic> and <italic>X. auripennis</italic>.</p></sec><sec><title>Results</title><p>A maximum of 4,429 unique amplicon sequence variants (ASVs) were detected from all samples, belonging to 10 different phyla. <italic>X. caerulea</italic> and <italic>X. auripennis</italic> shared similar bacterial community profiles, with Lactobacillaceae, Bifidobacteriaceae, and Orbaceae being dominant in their entire guts. <italic>X. caerulea</italic> and <italic>X. auripennis</italic> harbor a highly conserved core set of bacteria, including the genera <italic>Candidatus Schmidhempelia</italic> and <italic>Bombiscardovia</italic>. These two bacterial taxa from carpenter bees are closely related to those isolated from bumblebees. The LEfSe analysis showed that Lactobacillaceae, Bifidobacteriaceae, and the genus <italic>Bombilactobacillus</italic> were significantly enriched in the hindguts of both carpenter bees. Functional prediction suggested that the most enriched pathways were involved in carbohydrate and lipid metabolism.</p></sec><sec><title>Conclusions</title><p>Our results revealed the structure of the gut microbiota in two carpenter bees and confirmed the presence of some core bacterial taxa that were previously only found in the guts of social bees.</p></sec>